Q. What lavender would be best for making a hedge? I just bought a home and heard lavender is a natural repellent for scorpions and other insects. I'm trying to tackle my pest problems and landscaping renovation at the same time.
A. I think your selection will be restricted more by what is available locally. Stay away from English lavender in hot locations. English lavender would be better planted in the north or east sides in some light shade. Spanish and French lavender are generally more tolerant of the heat.
I am not sure what local nurseries are selling but lavender has been planted in our climate without any difficulties. It is fine in full sun but it may struggle in very hot locations such as against walls west or south facing. These plants will appreciate amending the soil at planting time.
Rock mulch is never a good idea with lavender. Amend the soil with compost at planting time and cover the surface of the soil with woodchip mulch. You might look for Rosemary and neem oils as a spray deterrent for bugs as well.